This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 90 |
| 2 | 2070 |
| 3 | 22530 |
| 4 | 151560 |
| 5 | 731502 |
| 6 | 2777370 |
| 7 | 8809110 |
| 8 | 24314490 |
| 9 | 60110030 |
| 10 | 135916002 |
| 11 | 285510150 |
| 12 | 563873400 |
| 13 | 1056789450 |
| 14 | 1893408750 |
| 15 | 3262336002 |
| 16 | 5431848930 |
| 17 | 8774904690 |
| 18 | 13799638910 |
| 19 | 21186110970 |
| 20 | 31830097752 |
| 21 | 46894786710 |